Six fire engines and around 40 firefighters were called to a fire at a food processing factory on Elveden Place in Park Royal.
The internal extraction system from the ground floor to the roof of the building was destroyed by fire. Around 150 people left the property before the Brigade arrived. There were no reports of any injuries.
The first of 10 calls to 999 was made by passers-by who saw flames coming from the roof at the rear of the factory.
Firefighters used thermal imaging cameras to check for fire spread and any remaining hot spots.
The Brigade was called at 0020 and the fire was under control by 0223. Fire crews from Acton, Park Royal, Wembley, Willesden, North Kensington and Chiswick fire stations attended the scene.
The cause of the fire is under investigation.